Heretofore, a working machine, such as a hydraulic excavator, is known that is provided with a plurality of circuit systems to each of which working oil is supplied from corresponding one of a plurality of hydraulic pumps. JP10-088627A discloses an excavation turning working machine in which a first pump, a second pump, and a third pump supply working oil to respective circuit systems.
Further, in some working machines, such as hydraulic excavators, there is a case where a split-flow pump is used in place of two hydraulic pumps. The split-flow pump has a single cylinder block provided with two separate discharge ports to allow working oil to be discharged to two systems at the same time.